The present invention relates to construction of an electronic calculator. In the sense of the present invention, an electronic calculator means, any electronic apparatus which is capable of performing an arithmetic operation in accordance with numeral and functional information introduced via a keyboard is included within the general field of the present invention and includes for example, a combined calculator and timekeeper, an electronic scale, an electronic price-calculating weight and the like. The following description sets forth details of the present invention in terms of only an electronic calculator.